As has been noticed in a few places, though without very much discussion or elaboration,1 Descartes’s basic epistemological approach is foundationalist in character: it views justification and knowledge as ultimately derivative from a set of basic or foundational elements whose justification does not depend in turn on that of anything else. For Descartes, as for many foundational-ists, the foundation for knowledge and justification consists of (i) a person’s immediate awarenesses of his or her own conscious states of mind, together with (ii) his or her a priori grasp of self-evidently true propositions. Beliefs deriving from these two sources require no further justification, whereas be-liefs about most or all other matters, and especially beliefs concerning objects and occurrences in the material world, require justification or reasons that ultimately appeal, whether directly or indirectly, to immediate experience and a priori insight.2 As the term “foundation” itself suggests, the underlying metaphor is an architectural one: think of a building or structure, perhaps a very tall one with many different levels, but all of them resting on a bottom level that does not rest in the same way on anything else.Most historical epistemological views have been broadly foundational-ist in character (though they have not always agreed with Descartes about the specific composition of the foundation). But in recent times a fairly widespread apparent consensus has developed to the effect that the whole foundationalist approach is deeply flawed and ultimately untenable.